common_load_preferences(): array;
common_save_preferences(array $prefs): bool;

Masquerade as a specific site (-d domain) and/or user (-u user) to retrieve the user preferences as JSON (-o format). Manipulate using jq, then save the preferences back declaring source input format (-i format) as JSON.

# jq isn't always installed
yum install -y jq
# set nexus.notify-create value to 1
cpcmd -i json common:save-preferences "$(cpcmd -o json common:load-preferences | jq -r '.nexus["notify-create"]=1')"

It's also possible to use PHP's serialize (serialize()/unserialize()) if the format is changed from json to serialize.

cpcmd -i serialize common:save-preferences "$(cpcmd -o serialize common:load-preferences | php -r '$prefs = unserialize(file_get_contents("php://stdin")); $prefs["nexus"]["notify-create"] = 1; echo serialize($prefs);')"

However it's clear to see JSON has its terse advantages.

See also

Collections

Covers jq examples (docs.apiscp.com)

jq Tutorial

Jump on a jq tutorial (stedolan.github.io)